Oil‐Water Separation Performance and Thermoregeneration of a Nanofibrous SiO2 Membrane Prepared by Sol‐Electrospinning

Abstract

AbstractThe discharge of oily wastewater seriously affects human health and the sustainable development of the ecological environment. Therefore, developing oil‐water separation materials capable of removing organic pollutants is imperative. In this study, we report the preparation of a SiO2 nanofiber membrane based on tetraethyl orthosilicate (TEOS) using a template‐free strategy combined with electrostatic spinning technology. The prepared SiO2 nanofiber membrane was characterized using SEM, EDX, FT‐IR, AFM, XRD, CA, and TG techniques. The prepared SiO2 nanofiber membranes exhibit excellent hydrophilicity (WCA=0°) in air and oleophobicity (UWOCA=136°) underwater, with excellent anti‐pollution properties for gravity‐driven oil‐water separation. The SiO2 nanofiber membrane can effectively separate different kinds of oil‐water mixtures with high water flux (4420 L m−2 h−1) and excellent separation efficiency (99.1 %), with a flux loss of 5.65 % after ten cycles, indicating excellent cycling stability. In addition, it can also be used to separate various oil‐in‐water emulsions stabilized by surfactants with a separation flux higher than 2079 L m−2 h−1 and a separation efficiency maintained at more than 97 %. During the separation of 150 mL lotion, the membrane was seriously scaled due to long‐term pollution. Simple water washing could not restore the membrane flux, and the irreversible scaling rate was 50.74 %, which seriously affected the continuous separation. However, due to the excellent thermal stability of SiO2 nanofiber membranes, oil contaminated membranes can be heated and regenerated, resulting in a flux recovery rate of nearly 100 %. Overall, this material has a wide range of potential applications in environmental protection, especially in the treatment of oily wastewater, due to its simple fabrication method, high flux, and superb oil resistance and recyclability.